Magnetic head supporting mechanism

ABSTRACT

A magnetic disc apparatus having a magnetic disc on which information is recorded, a magnetic head and a magnetic head supporting mechanism. The magnetic head supporting mechanism includes a slider having the magnetic head mounted thereon, a load beam having an arm mounting portion and a pivot, and a gimbal having a mounting portion on which the slider is mounted, two flexible finger portions spaced from the load beam and supporting the mounting portion so that the slider is rotatable with respect to the pivot, and a base end portion which is joined to the load beam. The load beam has two openings formed therein in proximity to the pivot which enable viewing of a back surface of the mounting portion which is opposite to a surface of the mounting portion of the gimbal on which the slider is mounted.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional application of U.S. application Ser. No.11/237,823, filed Sep. 29, 2005, which is a continuation of U.S.application Ser. No. 10/635,607, filed Aug. 7, 2003, now U.S. Pat. No.6,954,337, which is a continuation of U.S. application Ser. No.10/217,412, filed Aug. 14, 2002, now U.S. Pat. No. 6,621,663, which is acontinuation of U.S. application Ser. No. 09/812,788, filed Mar. 15,2001, now U.S. Pat. No. 6,552,877, which is a divisional of U.S.application Ser. No. 09/140,350, filed Aug. 26, 1998, now U.S. Pat. No.6,226,153, the subject matter of which is incorporated by referenceherein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magnetic-head supporting mechanismfor a magnetic-disc apparatus, and in particular, to a magnetic-headsupporting mechanism that is excellent in impact resistance.

2. Description of the Related Art It has been reported that when a largeimpact is applied to a conventional magnetic-disc apparatus in thedirection perpendicular to a disc surface, a slider jumps up from themagnetic disc surface, is tilted while floating, and falls from theangle of a slider floating rail to contact and damage the disc surface(IEEE TRANSACTION ON MAGNETICS Vol. 31, No. 6, pp. 3006 to 3008:NOVEMBER, 1995). This article also reports that a “jump stop” iseffectively provided on the slider in order to reduce the damage to thedisc caused by an impact.

In addition, JP-A-8-102159 discloses a mechanism comprising a pinprotrusion (a limiter section) on a cover or on a base of amagnetic-disc apparatus wherein if the magnetic-disc apparatus issubjected to an impact to oscillate a suspension having a magnetic headat its free end, the free end of the suspension contacts the pinprotrusion and is stopped from being further displaced toward the baseor cover.

According to the conventional mechanism, if the slider is subjected toan impact and leaves the disc surface, the jump height is restricted bythe jump stop or pin protrusion to a predetermined value or less. Anobject of this configuration is to reduce the speed or acceleration atwhich the slider collides against the disc in order to reduce the damageto the slider and disc upon the impact, thereby improving the impactresistance of the magnetic-disc apparatus.

On the other hand, the degree of damage depends on the magnitude of thespeed and acceleration at which the slider contacts the disc as well asthe extent of the contact area. That is, the contact area significantlyvaries depending on whether a floating surface (a surface that isopposed to the disc surface and on which a floating force is effected)of the slider contacts the disc surface in parallel or the sliderrotates and contacts the disc surface at the corners of its floatingsurface or at its bleed surface (a surface that is opposed to the discsurface and on which a floating force is not effected). Thus, even ifthe slider contacts the disc surface at the same speed and acceleration,the contact area pressure (stress) significantly varies depending on thecontact areas of the slider and disc surface, that is, the position ofthe slider in which it collides against the disc surface, resulting insignificantly different degrees of damage. The prior art does not takethis point into account.

OBJECT AND SUMMARY OF THE INVENTION

In view of this point, it is an object of this invention that when themagnetic-disc apparatus is subjected to a large impact to cause theslider to jump from the disc surface and the slider then re-contacts thedisc surface, the contacting position of the slider is controlled toprevent the contact area from being reduced in order to reduce contactdamage, thereby improving the impact resistance.

In other words, when the magnetic-disc apparatus is subjected to animpact to cause the slider to jump and the slider then re-contacts thedisc surface, the position (angle and state) of the slider is controlledto provide a sufficient contact area (prevent the contact area frombeing reduced) in order to reduce the contact area pressure (stress),that is, damage.

It is another object of this invention to improve the impact resistanceof the magnetic-disc apparatus and to provide a magnetic-head supportingmechanism that allows the slider to be easily mounted on the suspensionand that has an excellent assembly capability.

To achieve these objects, the magnetic-head supporting mechanismaccording to this invention is composed of a slider on which a magnetichead is mounted; and a suspension that holds the slider and that pressesthe slider against the disc surface from the rear surface of the slider(the surface opposite to the disc-opposed surface), the suspensionconsisting of a gimbal (also referred to as a “flexure”) and a loadbeam.

The gimbal is composed of a mounting portion on which the slider ismounted (normally, joined with an adhesive); a stage portion thatconnects to One end of the mounting portion; two flexible fingerportions extending along the respective sides of the mounting portionfrom the other end of the stage portion; and a joint portion thatconnects to the other end of the flexible finger portions to join theload beam and that is joined with the tip of the load beam (normally bymeans of spot welding).

The gimbal has a low rigidity sufficient to avoid restraining themovement of the slider in the out-of-plane direction perpendicular tothe floating surface of the slider, (perpendicular to the floatingsurface) while having a high rigidity in the in-plane direction(parallel to the floating surface).

The load beam consists of an arm mounting portion, a spring portion, anda flange portion, and the joint portion of the gimbal is joined with thetip of the flange portion. On the other hand, the other end of theflange portion connects to the spring portion, and the other end of thespring portion connects to the arm mounting portion that is mounted onan arm portion that is very rigid. A load generated in the springportion is transmitted through the flange portion, via a pivot (aprotrusion) provided at the tip of the flange portion to protrude in theslider direction, to the mounting portion of the gimbal mounted on therear surface of the slider. Since the mounting portion is joined withthe rear surface of the slider, the load transmitted to the mountingportion acts to press the slider. The load generated in the springportion is generated by bending the spring through a predetermined angleprior to installation in the magnetic-disc apparatus so that the springis installed approximately in parallel to the disc surface.

The slider is mounted on the load beam via the gimbal, as describedabove, and is pivotally supported by the pivot, so it freely rotatesaround the pivot in the out-of-plane direction perpendicular to thefloating surface.

The magnetic head supporting mechanism having the above mechanism has aroof portion formed by extending the tip of the flange portion of theload beam to the rear surface of the slider. Specifically, if the roofportion is projected onto the gimbal, its size is slightly smaller thanor approximately equal to that of the gimbal. In addition, the roofportion is formed by integrally extending the flat portion of the flangeportion, and is normally prevented from contacting the flexible fingerportions and stage portion of the gimbal. That is, the roof portion doesnot restrain the movement of the slider.

According to this configuration, even when a large impact is applied tothe magnetic-disc apparatus to cause the slider to jump from the discsurface and to start rotating around the pivot through a large angle,the gimbal, which rotates with the slider, contacts the roof portion torestrict the rotation of the slider. This enables the position (state)of the slider in which it contacts the disc surface after a jump to becontrolled. Specifically, the substantial rotation of the slider causesthe edges of the bleed surface of the slider (the four corners of theslider) or of the floating surface to contact the disc surface, therebypreventing the disc from being damaged due to a high contact areapressure (stress) caused by a small contact area.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general view of a magnetic-disc apparatus according to thisinvention;

FIG. 2 is a magnetic-head supporting mechanism according to thisinvention;

FIG. 3A is a detailed view of a tip of the magnetic-head supportingmechanism according to this invention;

FIG. 3B is a sectional view of a load beam in FIG. 3A taken along lineR-R;

FIG. 4 is a side view of the magnetic-head supporting mechanismaccording to this invention;

FIG. 5A is a top view of a roof portion of the load beam according tothis invention;

FIG. 5B is a side view of a roof portion of the load beam according tothis invention;

FIG. 6A is a top view of a gimbal shape according to this invention;

FIG. 6B is an enlarged view of a portion C in FIG. 6A;

FIG. 6C shows FIG. 6A as seen from direction D-D;

FIG. 7A is a sectional view of FIG. 3 taken along line VII-VII;

FIG. 7B shows a maximum rotation state of FIG. 7A;

FIG. 8A shows a maximum pitch angle according to a first embodiment;

FIG. 8B shows the maximum pitch angle of a conventional magnetic-headsupporting mechanism;

FIG. 9A compares a contact area obtained when the angle of a bleedportion is 90° with a contact area obtained when the angle of the bleedportion is 45°;

FIG. 9B shows a state in which the angle of the bleed portion is 90 or45°;

FIG. 10A is a top view of a load beam according to a second embodimentof this invention and FIG. 10A 1 is a cross-sectional view thereof;

FIG. 10B is a bottom view of the load beam according to the secondembodiment of this invention and FIG. 10B 1 is a cross-sectional viewthereof;

FIG. 11 is a top view of a load beam according to a third embodiment ofthis invention and FIG. 11A is a cross-sectional view thereof;

FIG. 12A is a top view of a load beam according to a fourth embodimentof this invention;

FIG. 12B is a side view of the load beam according to the fourthembodiment of this invention;

FIG. 13A is a top view of a load beam according to a fifth embodiment ofthis invention;

FIG. 13B is a sectional view of FIG. 13A taken along line C-C;

FIG. 14A is a top view of a gimbal portion according to the fifthembodiment of this invention;

FIG. 14B is a side view of FIG. 14A;

FIG. 15A shows a general configuration of the fifth embodiment of thisinvention;

FIG. 15B is a sectional view of FIG. 15A taken along line D-D;

FIG. 15C is a sectional view of FIG. 15A taken along line D-D, showing amaximum rotation state;

FIG. 16 is a top view of a load beam according to a sixth embodiment ofthis invention;

FIG. 17 is a perspective view of a seventh embodiment of this invention;

FIG. 18 is a sectional view of FIG. 17 taken along line A-A;

FIG. 19 is a side view showing an eighth embodiment of this invention;

FIG. 20 is a bottom view of FIG. 19 (without slider);

FIG. 21 describes the effects of this invention;

FIG. 22A shows a configuration of a conventional magnetic-headsupporting mechanism;

FIG. 22B shows a load beam in FIG. 22A;

FIG. 23A is a sectional view of FIG. 22A taken along line B-B; and

FIG. 23B shows a maximum rotation state of FIG. 23A.

DESCRIPTION OF THE EMBODIMENTS

A first embodiment of this invention is described with reference toFIGS. 1 to 9.

FIG. 1 shows a general view of a magnetic-disc apparatus in which amagnetic-head supporting mechanism according to a first embodiment ofthis invention is mounted.

A magnetic discs 1 on which information is recorded is laminated on aspindle 2. A magnetic head (not shown) used to record and reproduceinformation on and from the magnetic disc is mounted on a slider 4 of amagnetic-head supporting mechanism 5. The magnetic-head supportingmechanism 5 is joined with the arm 6. The magnetic head is placed at apredetermined radial position by a carriage 9 consisting of a pivotbearing 7 and a voice coil motor 8. These mechanisms are mounted in alunch-box-shaped base and are sealed by a cover (not shown). The presentmagnetic-head supporting mechanism improves impact resistance to enablerecording and reproduction at a high density even when the magnetic-discapparatus is configured as a portable type.

FIG. 2 shows the overall magnetic-head supporting mechanism 5 accordingto the first embodiment. An arm mounting portion 10 connects to a springportion 11, which connects to a flange portion 12. A constricted portion100 is provided at the tip of the flange portion 12, and a pivot 13 anda roof 14 are provided at the tip of the constricted portion 100. Thearm mounting portion 10, spring portion 11, and flange portion 12,constricted portion 100, pivot 13, and roof 14 are composed of a singlemember and are collectively referred to as a “load beam 101” below. Thisinvention is explained in conjunction with the pivot provided at the tipof a flat portion 12 a of the flange portion 12 for convenience. Bybending the spring portion 11 through a predetermined angle prior toinstallation in the apparatus and mounting it approximately in parallelto the disc surface during installation, a plunge load on the slider 4is generated by means of the flexure of the spring portion 11. Theplunge load is transmitted through the flange portion 12 via the pivot13 to the slider 4. Instead of providing the constricted portion 100,the tip side of the flat portion 12 a can be continuously tapered wherethe pivot and roof can be provided. The configuration and operation ofthe roof are described below.

FIG. 3A shows details of the tip of the magnetic-head supportingmechanism 5, and FIG. 3B shows the relationship between the flat portion12 a and a U-shaped bent portion 12b in a cross section of the load beam101 taken along line R-R. The constricted portion 100 is provided at thetip of the flat portion 12 a of the flange portion 12, and a portion ofthe flat portion 12 a that is closer to its tip than the constrictedportion has the pivot 13 and roof 14 thereon. In addition, the roof 14has windows 16 used to admit ultraviolet rays and to allow the slidermounting state to be observed. A gimbal 20 is provided under the roof14, and the slider 4 is mounted on the tip side of the gimbal 20 bymeans of adhesion. The width of the roof 14 is larger than orapproximately equal to that of the gimbal 20, and its tip extendsapproximately as far as the tip of the gimbal 20.

In addition, as shown in FIG. 3, the windows 16 enable the rear surfaceof the slider 4 to be directly observed. In the figure, the lateralsides 4a (side edges) of the slider 4 can be observed through thewidth-wise centers of the windows 16 along the longitudinal direction.Thus, when the roof 14 is provided on the gimbal 20, it can be easilydetermined whether the slider 4 is mounted on the gimbal 20 at apredetermined angle. An ultraviolet-hardening adhesive can be used sothat the mounting portion used to mount the slider 4 on the gimbal 20 isdirectly irradiated with ultraviolet rays (UV) through the windows 16 toharden the adhesive, thereby reducing the time required for adhesion andproviding a predetermined adhesion strength. Light can enter a diagonaldirection, so the direct underside (slider side) of the pivot 13-sideedges of the windows 16 approximately aligns with the edges of themounting portion used to mount the slider 4 thereon. The shapes andsizes of the mounting portion and windows are described below.

FIG. 4 shows a side view of a magnetic head supporting mechanismaccording to a first embodiment. A pivot 13 is provided beyond theconstricted portion 100 located on the tip side of the flat portion 12 aof the flange portion 12. The gimbal 20 is mounted under the flatportion. The flange-side end surface of the gimbal 20 is welded to theflat portion 12 a, while the other end reaches the slider 4 via a stagedportion 23, with the slider mounted with an adhesive on the mountingportion 24 connecting to the staged portion. The top of the pivot 13applies a load to the slider via the mounting portion 24.

FIG. 5 shows details of the roof portion of the load beam 101 accordingto the first embodiment. A sheet metal is etched to create the entireshape and windows, and the U-shaped bent portion of the flange 12b ismolded by means of press working. The pivot 13, which is molded by meansof press working, is located at the tip of the flat portion 12 a, andthe roof 14 is formed that have the two windows 16 around the pivot. Theroof 14 and pivot 13 are formed of the same sheet metal as in the flatportion 12 a.

FIG. 6 shows the shape of the gimbal used in this embodiment. The gimbal20 is composed of a joint portion 21 in order to join the load beam; twoflexible finger portions 22; and a staged portion 23; and a mountingportion 24 used to mount the slider 4. The flexible finger portions 22support the slider 4 without restraining the movement of the slider 4 inthe direction perpendicular to the slider floating surface (out-of-planedirection). The staged portion 23 prevents the slider 4 mounted on themounting portion 24 from contacting the flexible finger portions 22, andenables pivot supporting so that the slider 4 can move freely. FIGS. 6Band 6C show an enlarged side view of a portion C and a projection fromplane D-D.

The effects of this invention are described with reference to FIGS. 7,8, and 9.

FIG. 7A shows a cross section taken along line VII-VII in FIG. 3, andFIG. 7B shows the maximum rotation angle

r of the slider 4 in a roll direction. The thickness of the gimbaldepends on the size of the slider (precisely speaking, air filmrigidity), the height of the pivot depends on the stability of pressworking, and the thickness of the load beam is determined by the elasticmodulus of the spring portion. According to this invention, even if theslider is rotated by an external impact, the tips of the flexible fingerportions 22 contact the roof 14 to prevent the slider from rotatingthrough a predetermined angle or more, as shown in FIG. 7B.

As shown in FIG. 7A, the size of the roof may be slightly larger than orequal to the size of the flexible finger portions. The rotation angle isaffected by the gap between the roof 14 and the flexible finger portions22, and can be reduced by reducing this gap. Even when the roof 14 isconfigured to be is slightly smaller than the flexible finger portions22, a predetermined angle can be obtained by setting a smaller gap.

Then, the-maximum rotation angle

rMax in a roll direction is 3.2° (arctan (0.045/0.5)) if, for example,the roof width is 1.6 mm and if the gap between the roof 14 and theflexible finger portions 22 is 0.045 mm.

On the other hand, a conventional magnetic head supporting mechanism,which is shown in FIG. 22A, does not have a roof but only a pivot 13 atthe tip of the flange portion. Thus, nothing covers the top surface of aflexible finger portion 22 of the gimbal. For more clarity, FIG. 22Bshows only a conventional load beam. As is apparent from a comparisonbetween FIG. 22B and FIG. 5 for the first embodiment, the conventionalmagnetic head supporting mechanism does not include the roof portionaccording to this invention. In addition, the width of the conventionalpivot 13 mounting portion does not include the roof according to thefirst embodiment of this invention.

FIG. 23A shows a cross section taken along line B-B in FIG. 22A. Thisfigure shows that there is nothing on the top surface (opposed to theslider) of the flexible finger portion 22 that interferes with themovement of the portion 22, as described above. Thus, if the slider isrotated by an impact, the gimbal mounting portion 24 rotates until itcontacts the side edge of the pivot 13.

Thus, if, for example, the gap between the mounting portion 24 and theside edge of the pivot is 0.089 mm and the width of the side edge of thepivot is 0.72 mm, the maximum rotation angle of the slider reaches 14°(arctan (0.089/0.36)). This is about four times as large as the value ofthe roofed magnetic-head supporting mechanism (=14°/3.2°).

FIG. 9 shows the relationship between the angle and contact areameasured when the slider contacts the disc surface after rotatingthrough such a large angle. The horizontal axis indicates the rotationangle of the slider, while the vertical axis indicates the inverse ofthe contact area. This figure shows that as the angle value increases,the contact area decreases, that is, the contact area pressureincreases, resulting in severer damage to the disc surface.

In addition, as a condition for the above calculations, the angle of thebleed portion of the slider is set at 90° or this portion is chamferedat 45° (see FIG. 9B). When the contact area at a rotation angle of 14°is compared with the contact area at a rotation angles of 3°, this valueis much smaller at 3° (10% or less). This effect remains unchanged ifthe discharge end of the slider is chamfered at 45° (the angle of thebleed portion is 135°).

This invention can reduce the rotation angle of the slider down to 3°compared to 14° in the prior art, thereby reducing the damage to thedisc surface down to one-tenths or less.

FIGS. 8A and B show a comparison of the maximum pitch angle of the tipof the gimbal according to the first embodiment

=7°=arctan (0.06/0.5)) with a conventional maximum pitch angle

=15°=arctan (0.10/0.38)). In the first embodiment, even when the sliderrotates in a pitch direction (forward inclination), the tip of theflexible finger portion 22 contacts the roof 14 to limit the rotation toa small range. The contact angle during rotation is 7° (=arctan(0.06/0.5)) if, for example, the length from the pivot to the tip of theroof is 0.5 mm and if the gap between the roof and the flexible fingerportion 22 is 0.06 mm. Thus, the slider does not rotate through 7° ormore.

According to this embodiment, the tip of the roof extends approximatelyas far as the tip of the flexible finger portion 23. If the tip of theroof is extended beyond the tip of the flexible finger portion, forexample, to behind the magnetic head of the slider, the maximum pitchangle cannot be reduced and in fact, the weight of the load beamincreases to reduce the natural frequency of the magnetic-headsupporting mechanism or the access speed.

In addition, if a signal line from the magnetic head provided at therear end of the slider is drawn in the direction perpendicular to thefloating surface, that is, in the direction of the load beam and if theroof is extended to behind the magnetic head of the slider, then theroof may interrupt the routing of the signal line. Thus, it is mostpreferable that the tip of the roof 14 extend approximately as far asthe flexible finger portion of the gimbal.

As shown in FIG. 8B, the conventional apparatus has no roof, so thedistance from the top of the pivot to the tip of the load beam is shortand the mounting portion 24 rotates until it contacts the tip of theload beam. The contact angle during rotation is 15° if, for example, thelength from the pivot to the tip of the roof is 0.38 mm and if the gapbetween the roof and a mounting portion 24 is 0.1 mm. With sucharrangement the maximum rotation angle of pitch can be reduced to 46% ofthe conventional arrangement by providing the roof.

In addition, the above calculated angle varies with the height of thepivot and the shape of the gimbal or load beam, but the effects of theroof according to this invention remain unchanged.

As described above, in the first embodiment of this invention, themagnetic-head supporting mechanism includes the roof that controls theposition of the slider. Thus, after a large impact is effected on thedisc apparatus to cause the slider to jump, the position of the slidercan be controlled when it contacts the disc, thereby reducing thecontact area pressure between the slider and the disc. Thus, thisinvention can provide a magnetic-head supporting mechanism having a highimpact resistance and improve the impact resisting capability of themagnetic-disc apparatus in which the magnetic-head supporting mechanismis mounted. In addition, by providing an ultraviolet intake window usedto harden an adhesive and a window used to observe how the slider ismounted with the roof, the productivity of the magnetic head supportingmechanism can be improved.

A second embodiment of this invention is described with reference toFIGS. 10A and 10B. This figure shows only the roof portion of this,embodiment in detail. The other sites are the same as in the firstembodiment, so they are omitted. The second embodiment differs from thefirst embodiment in that it has a rotation angle adjustment groove 40 inthe roof portion.

This groove is provided on the flexible finger portion of the gimbal toadjust the gap between the flexible finger portion and the roof.Specifically, according to the first embodiment, the gap between theflexible finger portion 22 and the roof 14 is 0.045 mm and the maximumrotation angle is 3.2°, as shown in FIG. 7A. This gap can be controlledto adjust the contact angle.

According to the first embodiment, the height of the pivot is used tocontrol the gap. On the other hand, since the pivot is molded by pressworking, its height and accuracy are limited. The second embodimentincludes a staged roof 17 having the rotating angle adjustment groove 40in the gimbal-opposed surface of the roof according to the firstembodiment.

The depth of the rotation angle adjustment groove 40 can be varied tocontrol the gap. This eliminates the need to control the gap (rotationangle) and requires only the height of the pivot to be controlled,thereby increasing the degree of freedom. Furthermore, the depth of therotation angle adjustment groove can be accurately controlled by meansof machining or etching to accurately control the maximum rotationangle. For the impact-resisting magnetic-head supporting mechanism toachieve stable floating, when no impact is applied, the contact betweenthe gimbal and the roof must be avoided despite machining variationduring the manufacturing of the pivot, whereas when an impact isapplied, the slider must be stopped by minimizing the rotation angle.

This embodiment can meet this requirement because the staged roof can beused to control the gap between the gimbal and the roof. As describedabove, this embodiment can control the rotation angle of the slider toimprove the impact resistance as in the first embodiment, and can alsoimprove productivity using the ultraviolet incidence window and theadhesion condition observation window.

A third embodiment of this invention is described with reference to FIG.11. This embodiment differs from the second embodiment in that therotation angle adjustment groove 40 is staged by means of press working.Thus, the height of the staged roof is different from that of thewindows as shown in FIG. 11. On the other hand, the rotation angleadjustment groove 40 is provided in the top surface of the flexiblefinger portion of the gimbal via a predetermined gap as in the secondembodiment. The staged roof with the rotation angle adjustment groove 40improves the degree of freedom in design for the height of the pivot,thickness of the gimbal, and the thickness and length of the load beam,as in the second embodiment. In addition, since the staged roof can bepress-worked simultaneously with the pivot 13, this embodiment providebetter productivity (mass productivity) than the second embodiment. Thisembodiment also provides high impact resistance and mass productivity asin the first embodiment.

A fourth embodiment of this invention is described with reference toFIGS. 12A and 12B. This embodiment differs from the first embodiment inthat it uses a four-point pressing roof 19.

The roof 19 has four protrusions, the tip of which corresponds to thesize (position) of one of the four corners of the roof 14 according tothe first embodiment. The width 19 a of the four protrusions isapproximately the same as that of the gimbal. In addition, the tip ofthe protrusion extends approximately as far as the tip of the gimbal.Since only the four points of the gimbal are pressed, the ultravioletincidence window and adhesion condition observation window, which arerequired by the first embodiment, can be omitted to reduce the tareweight of the roof portion. Thus, the impact resistance and productivitycan be improved as in the first embodiment. Furthermore, the reducedweight of the roof portion precludes the natural frequency of themagnetic-head supporting mechanism from decreasing. This in turn enablesthe magnetic head to be positioned promptly and accurately.

A fifth embodiment of this invention is described with reference toFIGS. 13, 14, and 15. FIGS. 13A and 13B show details of a roof portionof a load beam according to the fifth embodiment. This invention differsfrom the first embodiment in that a ring-shaped roof 30 is provided atthe tip of the flat portion of the flange portion.

The ring-shaped roof 30 is shaped like a donut and has a window at itscenter. The pivot 13 is mounted at the tip of the flat portion as in thefirst embodiment, and the ring-shaped roof 30 extends from both sides ofthe flat portion of the pivot 13 to form ring-shaped roof. FIG. 13B alsoshows a cross section taken along the centerline C-C of the load beam.As shown in this cross section, the pivot 13 protrudes toward the slidermounting portion as in the first embodiment. In addition, the roof tip30 a is separated from the pivot 13 by a window 516.

In addition, the first embodiment includes the two windows 516 along thesides of the slider, but the fifth embodiment has only one by increasingthe size of the window 516 above the width of the slider. Thus, as inthe first embodiment, after the slider 4 has been mounted on a mountingportion 524 of the gimbal using an adhesive, ultraviolet rays can beirradiated through the window 516 to allow the adhesive to be hardenedin a short time. Furthermore, when mounted on the mounting portion 524,the slider 4 can be supported from the load beam side through the window516. This feature allows the slider to be mounted easily.

FIG. 14 shows the gimbal portion of the fifth embodiment. Its basicstructure is the same as that of the gimbal configuration (FIG. 6)according to the first embodiment, and this gimbal is composed of aflexible finger portion 522; a staged portion 523; and a mountingportion 524. This differs from the gimbal according to the firstembodiment in that the flexible finger portion is shaped like a ringwith a curvature and in that a constricted portion 524 a is provided inthe mounting portion 524 of the slider. The ring shape of the flexiblefinger portion enables the further reduction of the effect of therestraint of the movement of the slider in the out-of-plane directionperpendicular to the floating surface of the slider. In addition, theslider is mounted on the mounting portion 524 so as not to be caught bythe constricted portion 524 a. Thus, the constricted portion 524 a workslike the flexible finger portion 522 to enable the slider to besupported without restraining its movement perpendicular to its floatingsurface (pitching, rolling, vertical movement).

In summary, as the miniaturization of the slider advances, its air filmrigidity decreases so the gimbal is required to support the sliderwithout restraining its movement in the out-of-plane direction(perpendicular to the floating surface). Thus, the gimbal according tothis invention has the constricted portion 524 a to reduce the pitchingand rolling rigidity of the gimbal in order to support the slider withthe reduced restraint of its movement.

FIG. 15 shows a general view of the fifth embodiment. As shown in FIG.15A, the ring-shaped roof 30 is formed to overlap the top surface of theflexible finger portion 522, and the roof tip 30 a is formed togenerally overlap two staged portion 523 provided at the tip of thegimbal. The roof tip 30 a, however, does not extend beyond the tip ofthe gimbal.

FIG. 15B shows a cross section taken along line D-D in FIG. 15A. Thering-shaped roof 30 has approximately the same width as the flexiblefinger portion 522 so as to cover its top surface. The slider mountingsurface 524 can be viewed through the window 516 in the ring-shaped roof30. As described above, the slider mounting surface 524 can beirradiated with ultraviolet rays through the window 516 to harden theadhesive between the slider and the mounting surface in a short time.The slider is mounted directly under the mounting portion 524, so it isnot shown. Of course, ultraviolet rays may be directly applied to theadhesive or may be diagonally incident as reflected (scattered) light.

The width of the window 516 is larger than that of the mounting portion524 of the slider. Thus it is possible to support the mounting portionthrough the window 516 and it is easy to achieve the mounting portionthrough the window when the slider is mounted on the mounting portion.

The effects of this invention are described with reference to theexplanatory drawing in FIG. 15C. According to this embodiment, even ifan impact causes the slider to roll (lateral rotational movement), thering-shaped roof 30 provided on the flexible finger portion 522restrains the movement of the slider to prevent it from rotating througha large angle, as in the first embodiment. This feature in turn reducesthe contact area ratio shown in FIG. 9 and thus contact damage to thedisc.

In addition, with respect to the pitching movement (longitudinalrotational movement) of the slider caused by an impact, the roof tip 30a covers the tip of the gimbal, so the gimbal, which rotates with theslider, contacts the roof to hinder the slider from rotating through alarge angle in the pitching direction. This feature reduces the contactarea ratio and thus contact damage to the disc, as described above.

Since the mechanical rigidity of the roof is higher than that of thegimbal, the gimbal, which moves with the slider, can of course beprecluded from being deformed. Again, what is important in thisembodiment is that the tip of the roof does not extend beyond the tip ofthe gimbal and that the roof has approximately the same shape as thegimbal. This configuration minimizes the increase in the mass of theload beam due to the provision of the roof and reduces the rotation ofthe slider caused by an impact. If the roof is larger than the gimbal,the mass of the load beam increases to significantly increase thereduced mass of the head from the rotational center of the carriage,thereby reducing the data access speed.

In this case, the natural frequency and the positioning accuracy of themagnetic head also decrease. Furthermore, even if the roof is largerthan the gimbal, its effects are still the same as those of a roof thatis as large as the gimbal. This is because the rotation angle restrainedby the roof is not changed by setting the width of the roof larger thanthat of the gimbal.

As described above, this embodiment provides effects similar to those ofthe first embodiment. It also can provide an impact-resistingmagnetic-head supporting mechanism optimal for a slider of a small airfilm rigidity. FIG. 16 shows a sixth embodiment of this invention. Thisembodiment differs from the fifth embodiment in that a window 31 isprovided in a roof 630. The window 31 serves to reduce the weight of theroof. This configuration can reduce the inertia moment of themagnetic-head supporting mechanism that uses the pivot bearing 7 of thecarriage 9 as a rotational center to enable fast seek operations.

If the external impact has a large value, the roof is deformed andcannot control the position of the slider. To solve this problem, therigidity of the roof must be improved. Although the width or thicknessof the roof can be increased to improve its static rigidity, doing thisincreases the tare weight of the roof and makes it too flexible (adecrease in dynamic rigidity). In addition, the inertia moment increasesthat uses the pivot bearing 7 as a rotational center. This embodimentprovides the window 31 in the roof 630 to improve the rigidity withoutincreasing the mass of the roof 630. Consequently, the impact resistanceof the magnetic-head supporting mechanism can be further improved.

FIGS. 17 and 18 show a seventh embodiment of this invention. Thisembodiment differs from the first embodiment in that the gimbal and theload beam are integrated together and that the pivot is omitted. Aslider 704 is mounted on a mounting portion 724, which connects to ahorizontal frame 725, and two flexible finger portions 722 extend fromthe respective sides of the horizontal frame to connect to a flangeportion 712. At a slider-side end of a flat portion 712 a of the flange,a roof 740 is provided over a rear surface 704 a of the slider. The roof740 is molded simultaneously with the press working of an L-shaped bentportion 712 b of the flange portion 712. FIG. 18 shows that the roof 740is provided over the rear surface 704 a of the slider. The roof 740 hasthe same effects as in the first embodiment and prevents the slider 704from rotating through a large angle due to an impact. That is, the roof740 restrains the rotation of the slider to reduce the contact anglebetween the slider and the disc. Thus, this embodiment can improveimpact resistance as in the first embodiment.

An eighth embodiment of this invention is described with reference toFIGS. 19, 20, and 21. In FIG. 20 the slider is not mounted. Thisembodiment differs from the seventh embodiment in that instead of theroof, a flange portion 812 is joined with a mounting portion 824 using aFPC 50. The FPC 50 has a loop-like flexed portion 50 a so as not tohinder the slider from floating.

If an impact is input, the flexed portion 50 a of the FPC 50 restrainsthe movement of the slider 4 as shown in FIG. 21. This prevents theslider 4 from rotating through a large angle due to the impact. Thus,this embodiment provides effects similar to those of the seventhembodiment. Of course, by providing the roof as shown in the first toseventh embodiments, the rotation of the slider caused by the impact canbe reliably restrained. Although this embodiment connects the mountingportion 824 and the flange portion 812 together using the FPC, similareffects can be obtained using an elastic material other than the FPCthat is not very rigid and that can resist tensile force. The FPC ismounted on the mounting portion 824 and the flange portion 812 by usingan adhesive agent. The loop-like flexed portion 50 a, mounting portion824, and horizontal frame 825 shown in FIG. 21 are collectively referredto as a “flexure”. The FPC 50 may be integrally formed with the FPC (notshown) for writing or reading signals of the magnetic head.

This invention can control the contact angle between the slider and thedisc, thereby providing a magnetic-head supporting mechanism that canreduce damage to the slider and disc caused by their contact in order toprovide high impact resistance, that exhibits high productivity usingthe ultraviolet incidence window, adhesion condition observation window,and slider holding window, and that is suitable for a small slider dueto the decrease in the rigidity of the gimbal.

1. A magnetic disc apparatus having a magnetic disc on which informationis recorded, a magnetic head used to at least one of record theinformation to said magnetic disc and reproduce the information fromsaid magnetic disc, and a magnetic head supporting mechanism supportingsaid magnetic head on said magnetic disc, said magnetic head supportingmechanism comprising: a slider having said magnetic head mountedthereon; a load beam having an arm mounting portion and a pivot; and agimbal having a mounting portion on which said slider is mounted, twoflexible finger portions spaced from said load beam and supporting saidmounting portion so that said slider is rotatable with respect to saidpivot, and a base end portion which is joined to said load beam; whereinsaid load beam has two openings formed therein in proximity to saidpivot which enable viewing of a back surface of said mounting portionwhich is opposite to a surface of said mounting portion of said gimbalon which said slider is mounted.
 2. A magnetic disc apparatus accordingto claim 1, wherein each opening is provided on opposite sides withrespect to said pivot.
 3. A magnetic disc apparatus according to claim1, wherein said arm mounting portion, said pivot and said elongationportions are made from a single thin plate.
 4. A magnetic disc apparatusaccording to claim 1, wherein a distance between furthest spaced edgesof said two openings is larger than a width of said slider.